1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Glue Code for 3-way parallel assembler optimized version of Twofish
4 *
5 * Copyright (c) 2011 Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
6 */
7
8#include <asm/cpu_device_id.h>
9#include <crypto/algapi.h>
10#include <crypto/twofish.h>
11#include <linux/crypto.h>
12#include <linux/export.h>
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/types.h>
16
17#include "twofish.h"
18#include "ecb_cbc_helpers.h"
19
20EXPORT_SYMBOL_GPL(__twofish_enc_blk_3way);
21EXPORT_SYMBOL_GPL(twofish_dec_blk_3way);
22
23static int twofish_setkey_skcipher(struct crypto_skcipher *tfm,
24 const u8 *key, unsigned int keylen)
25{
26 return twofish_setkey(tfm: &tfm->base, key, key_len: keylen);
27}
28
29static inline void twofish_enc_blk_3way(const void *ctx, u8 *dst, const u8 *src)
30{
31 __twofish_enc_blk_3way(ctx, dst, src, false);
32}
33
34void twofish_dec_blk_cbc_3way(const void *ctx, u8 *dst, const u8 *src)
35{
36 u8 buf[2][TF_BLOCK_SIZE];
37 const u8 *s = src;
38
39 if (dst == src)
40 s = memcpy(buf, src, sizeof(buf));
41 twofish_dec_blk_3way(ctx, dst, src);
42 crypto_xor(dst: dst + TF_BLOCK_SIZE, src: s, size: sizeof(buf));
43
44}
45EXPORT_SYMBOL_GPL(twofish_dec_blk_cbc_3way);
46
47static int ecb_encrypt(struct skcipher_request *req)
48{
49 ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
50 ECB_BLOCK(3, twofish_enc_blk_3way);
51 ECB_BLOCK(1, twofish_enc_blk);
52 ECB_WALK_END();
53}
54
55static int ecb_decrypt(struct skcipher_request *req)
56{
57 ECB_WALK_START(req, TF_BLOCK_SIZE, -1);
58 ECB_BLOCK(3, twofish_dec_blk_3way);
59 ECB_BLOCK(1, twofish_dec_blk);
60 ECB_WALK_END();
61}
62
63static int cbc_encrypt(struct skcipher_request *req)
64{
65 CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
66 CBC_ENC_BLOCK(twofish_enc_blk);
67 CBC_WALK_END();
68}
69
70static int cbc_decrypt(struct skcipher_request *req)
71{
72 CBC_WALK_START(req, TF_BLOCK_SIZE, -1);
73 CBC_DEC_BLOCK(3, twofish_dec_blk_cbc_3way);
74 CBC_DEC_BLOCK(1, twofish_dec_blk);
75 CBC_WALK_END();
76}
77
78static struct skcipher_alg tf_skciphers[] = {
79 {
80 .base.cra_name = "ecb(twofish)",
81 .base.cra_driver_name = "ecb-twofish-3way",
82 .base.cra_priority = 300,
83 .base.cra_blocksize = TF_BLOCK_SIZE,
84 .base.cra_ctxsize = sizeof(struct twofish_ctx),
85 .base.cra_module = THIS_MODULE,
86 .min_keysize = TF_MIN_KEY_SIZE,
87 .max_keysize = TF_MAX_KEY_SIZE,
88 .setkey = twofish_setkey_skcipher,
89 .encrypt = ecb_encrypt,
90 .decrypt = ecb_decrypt,
91 }, {
92 .base.cra_name = "cbc(twofish)",
93 .base.cra_driver_name = "cbc-twofish-3way",
94 .base.cra_priority = 300,
95 .base.cra_blocksize = TF_BLOCK_SIZE,
96 .base.cra_ctxsize = sizeof(struct twofish_ctx),
97 .base.cra_module = THIS_MODULE,
98 .min_keysize = TF_MIN_KEY_SIZE,
99 .max_keysize = TF_MAX_KEY_SIZE,
100 .ivsize = TF_BLOCK_SIZE,
101 .setkey = twofish_setkey_skcipher,
102 .encrypt = cbc_encrypt,
103 .decrypt = cbc_decrypt,
104 },
105};
106
107static bool is_blacklisted_cpu(void)
108{
109 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL)
110 return false;
111
112 switch (boot_cpu_data.x86_vfm) {
113 case INTEL_ATOM_BONNELL:
114 case INTEL_ATOM_BONNELL_MID:
115 case INTEL_ATOM_SALTWELL:
116 /*
117 * On Atom, twofish-3way is slower than original assembler
118 * implementation. Twofish-3way trades off some performance in
119 * storing blocks in 64bit registers to allow three blocks to
120 * be processed parallel. Parallel operation then allows gaining
121 * more performance than was trade off, on out-of-order CPUs.
122 * However Atom does not benefit from this parallelism and
123 * should be blacklisted.
124 */
125 return true;
126 }
127
128 if (boot_cpu_data.x86 == 0x0f) {
129 /*
130 * On Pentium 4, twofish-3way is slower than original assembler
131 * implementation because excessive uses of 64bit rotate and
132 * left-shifts (which are really slow on P4) needed to store and
133 * handle 128bit block in two 64bit registers.
134 */
135 return true;
136 }
137
138 return false;
139}
140
141static int force;
142module_param(force, int, 0);
143MODULE_PARM_DESC(force, "Force module load, ignore CPU blacklist");
144
145static int __init twofish_3way_init(void)
146{
147 if (!force && is_blacklisted_cpu()) {
148 printk(KERN_INFO
149 "twofish-x86_64-3way: performance on this CPU "
150 "would be suboptimal: disabling "
151 "twofish-x86_64-3way.\n");
152 return -ENODEV;
153 }
154
155 return crypto_register_skciphers(algs: tf_skciphers,
156 ARRAY_SIZE(tf_skciphers));
157}
158
159static void __exit twofish_3way_fini(void)
160{
161 crypto_unregister_skciphers(algs: tf_skciphers, ARRAY_SIZE(tf_skciphers));
162}
163
164module_init(twofish_3way_init);
165module_exit(twofish_3way_fini);
166
167MODULE_LICENSE("GPL");
168MODULE_DESCRIPTION("Twofish Cipher Algorithm, 3-way parallel asm optimized");
169MODULE_ALIAS_CRYPTO("twofish");
170MODULE_ALIAS_CRYPTO("twofish-asm");
171

source code of linux/arch/x86/crypto/twofish_glue_3way.c